<nz-input-group nzSearch [nzAddOnAfter]="suffixIconButton">
  <input type="text" nz-input placeholder="请输入课程号"  #course/>
</nz-input-group>
<ng-template #suffixIconButton>
  <button nz-button nzType="primary" nzSearch (click)="getStudents(course.value)" routerLink="./{{course.value}}"><i nz-icon nzType="search"></i></button>
</ng-template>
<router-outlet></router-outlet>
